cancer lecture

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					 How Cancers Develop and Spread
• Cancer develops only in cells with damaged
  genes (mutations).
   – Mutations can be inherited or caused by
     exposure to:
         –Low-dose radiation
         –Drugs
         –Toxic chemicals
   – Infection with certain viruses can cause
     mutations.
   – Lifestyle plays a major role in cancer
     prevention.
 How Cancers Develop and Spread
          (continued)

• Cells that begin to grow abnormally but
  are not yet cancer cells, may form benign
  tumors.
  – Benign tumors are surrounded by a fibrous
    capsule, and they do not spread or invade
    surrounding tissues.
    • Benign tumors are usually not life-threatening
      unless they interfere with vital processes.
    Cancer Detection and Staging

• Cancer screening is an examination to detect
  cancer before a person has symptoms.
• American Cancer Society recommends
  screening for early detection, particularly for
  high-risk people or people with symptoms.
   – Visual examination
   – Self-examination
   – Clinical (physician) examination
   – Laboratory testing
   – Scans (MRI, CAT)
                Lung Cancer
• Tobacco smoking is the leading cause of various
  cancers.
• 30% of cancer deaths, including 87% of lung
  cancer deaths, are attributed to tobacco use.
• Lung cancer is the leading cause of cancer
  deaths in the United States.
• Smoking cigarettes is most common cause.
• Women are more susceptible to lung cancer than
  men due to presence of the GRPR gene, which is
  linked to the abnormal growth of lung cells and is
  more active in women.
       Lung Cancer (continued)
• Signs and symptoms
  – In the early stages, signs and symptoms may
    be difficult to detect.
     • Cigarette smokers may have chronic
       cough or chronic bronchitis
     • Risk factors and prevention
  – Risk increases with:
     • The number of cigarettes smoked/day
     • The number of years a person smokes
     • How deeply the smoker inhales
     • Smoking high-tar or unfiltered cigarettes
       Lung Cancer (continued)

• Quitting tobacco use reduces lung
  cancer risk, but it never returns to that of
  a nonsmoker.
• Passive smoking may increase
  nonsmokers’ risk of lung cancer.
   – Environmental tobacco smoke is
     associated with 20% to 30% increase
     in lung cancer risk.
• Asbestos and radon exposure also
  increase risk.
         Cancers Related to Diet
About one-third of cancer deaths in the
United States that occur annually are due to
nutrition and physical activity factors.

For people who do not use tobacco, diet, and
physical activity are the most important
modifiable determinants of cancer risk.
Ex. Colorectal (3rd most deadly cancer in
U.S.)
                Breast Cancer
• Breast cancer occurs primarily in women.
• Signs and symptoms involve changes in breast tissue:
      • Risk factors
– Family history
     • Women with mothers, sisters, or daughters
       who have breast cancer
– Age
     • Rare before age 20
     • Risk increases throughout the 20s
     • Rises dramatically during the 30s through
       mid-70s (majority or cases occur in women
       40 and over)
     • Drops significantly after mid-70s
             Cervical Cancer
• A causal association exists between infection
  with human papillomavirus (HPV) and
  cervical cancer.
   – Causes genital warts
   – Is sexually transmitted
   – Risk of infection increases with an
     increased number of sexual partners
     and/or non-monogamous partners
   – Women who became sexually active
     before age 17 have higher risk
      Cervical Cancer (continued)
• Long-term use of oral contraceptives is
  associated with an increased risk of cervical
  cancer.
• In 2006, the Food and Drug Administration (FDA)
  approved a vaccine to prevent cervical cancer.
  – The vaccine, Gardasil, prevents infection with four
    types of HPV.
• The American Cancer Society (ACS)
  recommends that all women should have annual
  Pap tests three years after their first vaginal
  intercourse but not later than age 21.
 Cancers Related to Ultraviolet
          Radiation
•Related to exposure to ultraviolet (UV)
radiation from the sun as well as tanning beds.

•Three types of UV radiation: UVA, UVB, and
UVC. All types are harmful and have potential
to cause skin cancer.

•UVA is associated with sunburn, skin cancer
formation, and premature aging effects.
              Skin Cancer
• Related to exposure to ultraviolet (UV)
  radiation from the sun as well as tanning
  beds.
• Three types of UV radiation: UVA, UVB,
  and UVC.
• All types are harmful and have potential
  to cause skin cancer.
• UVA is associated with sunburn, skin
  cancer formation, and premature aging
  effects.
       Skin Cancer (continued)
  – Artificial UV sources may also generate
    UVC rays
     • UVC is potent cancer-causing radiation
     • Earth’s atmosphere filters natural UVC
• Prevention
  – Limit sun exposure
  – Use sunscreens
  – Where protective clothing when exposed to
    sunlight
  – Avoid artificial sources of UV light (i.e.,
    tanning beds).
  Types of Skin Cancer (continued)

• If you are high risk for malignant melanoma,
  check skin regularly for skin legions that:
       •   Are asymmetrical (A)
       •   Have irregular borders (B)
       •   Have multiple colors (C)
       •   Have a diameter greater than pencil eraser (D)
• Prevention
  –   Limit sun exposure
  –   Use sunscreens
  –   Where protective clothing when exposed to sunlight
  –   Avoid artificial sources of UV light (i.e., tanning beds)
         Reducing Cancer Risk

• Eat a diet low in fat and red meats, especially
  high-fat and processed meats.
• Eat a variety of fruits and vegetables daily.
• Follow ACS’s recommendations for cancer
  screening tests.
• Men should conduct monthly testicular self-
  examinations.
• Know warning signs of cancer and see your
  health care provider immediately if you detect
  any.
 Reducing Cancer Risk (continued)

• Sexually active people should use condoms to
  avoid contacting HPV.
• Maintain a healthy weight.
• Women should consult with their health care
  providers about risks of using oral
  contraceptives or hormone replacement
  therapy.
• Exercise most days of the week.
• When in the sun, takes steps to limit UV
  radiation exposure.
    Reducing Cancer Risk (continued)
•   Don’t smoke or chew tobacco.
•   Avoid secondhand smoke.
•   Don’t drink excessive amounts of alcohol.
•   Avoid unnecessary exposure to ionizing
    radiation, such as x-rays and UV light.
•   Don’t lie in the sun or tanning beds.
•   Avoid direct sun exposure between 10 a.m. and
    4 p.m.
•   Avoid exposure to toxic chemicals and fumes.
•   Avoid asbestos dust and radon gas.
•   Avoid eating cured or smoked meats.

				
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posted:6/27/2012
language:English
pages:17